This proposal seeks continued funding for studies of: i) structural and functional properties of the brainstem auditory pathways; and ii) the embryology of the auditory pathways. Experiments on the normal structural organization are designed to yield better understanding of the role(s) of inhibitory GABAergic pathways for coding the temporal properties of acoustic stimuli. Detailed anatomical and physiological experiments are proposed. Embryological studies use chick embryos and mice. Studies are designed to examine the early development and migration of CNS auditory neurons and to explore the roles of the two families of growth factor receptors on the development of neural pathways for acoustic information processing.